AndyObtiva/glimmer-dsl-swt

# Copyright (c) 2007-2024 Andy Maleh
#
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# a copy of this software and associated documentation files (the
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# without limitation the rights to use, copy, modify, merge, publish,
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# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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require 'glimmer-dsl-swt'

# This class declares a `greeting_label` custom widget (by convention)
class GreetingLabel
  include Glimmer::UI::CustomWidget
  
  # multiple options without default values
  options :name, :colors
  
  # single option with default value
  option :greeting, default: 'Hello'
  
  # internal attribute (not a custom widget option)
  attr_accessor :label_color
  
  def can_handle_observation_request?(event, &block)
    event.to_s == 'on_color_changed' || super
  end
  
  def handle_observation_request(event, &block)
    if event.to_s == 'on_color_changed'
      @color_changed_handlers ||= []
      @color_changed_handlers << block
    else
      super
    end
  end
  
  before_body do
    @font = {height: 24, style: :bold}
    @label_color = :black
  end
  
  after_body do
    return if colors.nil?
    
    @thread = Thread.new do
      colors.cycle do |color|
        self.label_color = color
        @color_changed_handlers&.each {|handler| handler.call(color)}
        sleep(1)
      end
    end
  end
  
  body {
    # pass received swt style symbols through to label to customize (e.g. :center to center text)
    label(*swt_style_symbols) {
      text "#{greeting}, #{name}!"
      font @font
      foreground <=> [self, :label_color]
      
      on_widget_disposed do
        @thread&.kill # safe since it does not involve data
      end
    }
  }
  
end

# including Glimmer enables the Glimmer DSL syntax, including auto-discovery of the `greeting_label` custom widget
include Glimmer

shell {
  fill_layout :vertical
  
  minimum_size 215, 215
  text 'Hello, Custom Widget!'
  
  # custom widget options are passed in a hash
  greeting_label(name: 'Sean')
  
  # pass :center SWT style followed by custom widget options hash
  greeting_label(:center, name: 'Laura', greeting: 'Aloha') #
  
  greeting_label(:right, name: 'Rick') {
    # you can nest attributes under custom widgets just like any standard widget
    foreground :red
  }
  
  # the colors option cycles between colors for the label foreground every second
  greeting_label(:center, name: 'Mary', greeting: 'Aloha', colors: [:red, :dark_green, :blue]) {
    on_color_changed do |color|
      puts "Label color changed: #{color}"
    end
  }
}.open